TUESDAY, March 24, 2015 (HealthDay News) -- Using stents rather than medication alone to keep narrowed arteries open in the brain may actually increase patients' risk of stroke, according to the results of a new trial.

The study involved more than 100 patients at risk of stroke because of what's called intracranial arterial stenosis -- plaque build-up in the artery walls in the brain. Those who received balloon-expandable stents -- tiny, mesh tubes like those used to open heart arteries -- were more than twice as likely to suffer a stroke or ministroke as patients treated with two blood thinners, Plavix and aspirin.

Moreover, in the month after the procedure, 8.6 percent of the stent patients suffered from bleeding in the brain and about 5 percent died, versus none of those who were treated with drugs.

"The current technology with balloon-mounted stent is very limited and is not recommended for patients with stroke or ministroke secondary to a narrowed brain artery," said the lead researcher, Dr. Osama Zaidat, an associate professor of neurology at the Medical College of Wisconsin in Milwaukee.

"For those people with symptomatic intracranial stenosis, medical [drug] therapy is the treatment of choice," he said.

The report was published in the March 24/31 issue of the Journal of the American Medical Association.

For the study, Zaidat and colleagues randomly assigned 112 patients with narrowed brain arteries to take the blood thinner Plavix (clopidogrel) plus aspirin or the stenting procedure plus medication.

The trial -- funded by California-based Micrus Endovascular Corp., the stent maker -- was halted at 112 patients after the results of another trial also showed that stents were linked to more strokes than they prevented. The new trial had been designed to enroll 250 patients, researchers said.

In the current study, about 24 percent of the stent patients suffered a stroke within 30 days compared to less than 10 percent of those treated with Plavix and aspirin, the researchers found.

After a year, 36 percent of those who received a stent had had a stroke or ministroke, compared with 15 percent of those treated with drugs.

"This second failed trial reinforces the conclusion that at present, [drug] therapy is much better than angioplasty and stenting for patients with a narrowing of an artery inside their head," said Dr. Colin Derdeyn, professor of radiology at Washington University School of Medicine in St. Louis.

That's "the way to go for patients with a recent stroke or ministroke and a blockage of a brain artery, as appealing as it is to want to go in and open the blockage," said Derdeyn, co-author of an accompanying journal editorial.

But another brain expert isn't ready to rule out stents altogether for stroke prevention, although he agreed more research is needed for optimal results.

"We have good data that putting stents in heart arteries are really good for treating patients with a heart attack or at risk of having a heart attack," said Dr. Mark Alberts, a professor of neurology and neurotherapeutics at the University of Texas Southwestern Medical Center in Dallas.

"Treating arteries in the brain is much more challenging, probably because the arteries are different, or because the disease may be different," Alberts added.

"We need to do a better job either with patient selection or with the technology or with the procedure itself, because clearly this is not working," he said.

Plaque build-up inside the artery wall is a common cause of repeated strokes, even with drug therapy, the researchers say.

Symptoms of artery build-up, which are similar to signs of ministroke, can include facial weakness or droop, especially on one side; arm or leg weakness; tingling; numbness, especially on one side, and slurred speech.